Vehicles use a variety of structures to protect the vehicle's occupants during a crash as well as minimize vehicle damage and simplify post-crash repairs. In general, these structures control how crash energy is transmitted through the vehicle and, more particularly, how crash energy is transmitted into the passenger compartment. Additional structures, such as seat belts, head restraints and air bags, are used to restrain passenger movement during a crash, thereby preventing the passengers from hurting themselves as their bodies react to the crash forces.
In recent times, efforts have also been made to provide protection for pedestrians that are in proximity to a moving vehicle. For example, a variety of techniques are now in use that limit the risk of a vehicle backing up and hitting a pedestrian. These techniques may utilize a pedestrian warning system such as an audible and distinct sound that is emitted by the vehicle when it is in reverse (e.g., a continuous series of beeps), thus helping pedestrians to recognize and react to an approaching vehicle. Alternately, some techniques are designed to provide additional warnings to the driver of the reversing vehicle, these techniques proving especially useful for eliminating driver blind spots. Such techniques may use proximity sensors that warn the driver, or automatically engage the brakes, when the reversing vehicle is about to collide with someone or something. Rear view cameras are another often used safety feature that provides the driver with an alternate view of their rearward surroundings whenever the car is in reverse.
In addition to attempting to minimize pedestrian accidents that occur when a car is backing up, recent advances in vehicle safety include design features that are intended to minimize the severity of accidents involving pedestrians hit by the front of the vehicle, i.e., head-on collisions with the vehicle. Typically at high speeds, a pedestrian involved in such a collision is thrown over or to the side of the on-coming vehicle. At lower speeds, however, the pedestrian tends to crumple over the front of the car, thereby causing the pedestrian's head to impact the vehicle's hood. Even at low speeds such accidents are often fatal.
A variety of different approaches have been investigated that are designed to minimize the impact force in a pedestrian/vehicle accident. For example, U.S. Pat. No. 7,303,040 discloses an active hood system that is designed to minimize impact force by moving the vehicle hood into an elevated position within 15 to 30 milliseconds of the detection of a collision or an accident between a pedestrian and the vehicle. By elevating the hood, the distance between the hood and the pedestrian is lessened, resulting in a lower impact force. In one of the disclosed embodiments, the hood is elevated in stages, with the last stage of movement being dampened.
U.S. Pat. No. 5,988,305 discloses an alternate method of minimizing the severity of head impact injuries in pedestrian/vehicle accidents, the disclosed approach utilizing a hood panel that is designed to absorb impact energy at an ideal rate. A variety of hood panel designs are disclosed, each of which includes an outer panel and an absorber mounted beneath the panel that is designed to absorb the impact energy during panel deformation.
U.S. Pat. No. 8,118,352 discloses a hood liner that stiffens the hood along its periphery. Within the liner is a hollow portion with a weakened bottom or side wall. During impact the weakened wall breaks, allowing deflection of the hood and reduced impact force.
While a variety of structures have been designed that are intended to lessen the severity of injuries that result from pedestrian/vehicle accidents, these techniques tend to be relatively complex, thus increasing manufacturing costs. Additionally these structures are not designed to provide a water tight seal between the hood and the underlying compartment. Accordingly, what is needed is a simple technique for reducing head impact force during a pedestrian/vehicle collision, while achieving a water tight seal. The present invention provides such a structure.